1. Field of the Invention
The present invention relates to a broadcast service system in a radio network using the Bluetooth technology.
2. Description of the Related Art
In recent years, the Bluetooth technology has been developed as a standard wireless technology for exchanging data such as video and audio data. The Bluetooth will be mounted on digital devices such as portable telephones, note PCs, digital home electronics, etc., and realize short distance radio communications among them.
The Bluetooth utilizes the carrier frequency of 2.4 GHz band, and the frequency hopping type spectrum spreading scheme. Namely, in the Bluetooth, there are 79 channels in 1 MHz band and the interferences with the other radio communications are prevented by switching these channels at most 1600 times per second.
Consequently, in the case of connecting the Bluetooth compatible devices (which will be referred to as Bluetooth units hereafter), there is a need to match the frequency hopping patterns between them. To this end, a Bluetooth unit that determines the frequency hopping pattern (which will be referred to as a master hereafter) and a Bluetooth unit this carries out communications according to the hopping pattern determined by the master (which will be referred to as a slave hereafter) will be set in a state capable of carrying out communications through processes called inquiry and page.
Now, the Bluetooth units can be connected by a point-to-point scheme or by a point-to-multipoint scheme. An active member address in 3 bits will be allocated to each slave connected to the master at a time of communications with the master. Consequently, in the point-to-multipoint connection, it is possible to connect seven slaves to one master.
However, because the number of slaves that can be connected to the master in the point-to-multipoint connection is limited to seven, there has been a problem that it is difficult for the master to provide the broadcast type service.
Thus, conventionally, in the case of constructing the radio network using the Bluetooth technology, there has been a problem that the broadcast type service cannot be provided due to the limitation that only seven slaves can be connected to the master.